Process of preparing soda-lime to be used in the manufacture of pure hydrogen



Patented Get. 13, 1931 JULIEN BELLAY, OF BRUSSELS, BELGIUM PROCESS OF PREPARING SODA-LIME TO BE USED IN THE IEANUFACTURE OF PURE HYDROGEN No Drawing. Original application filed January 13, 1928, Serial No. 246,558, and in Belgium January 26, 1927. Divided and this application filed April 30, 1229.

v the present application is a division, and the invention has for its object a process of preparing such special preparation of soda-lime.

By definition soda-lime is a mixture of lime and sodium hydroxide obtained by pouring a solution of sodium hydroxide upon calcium oxide and calcining the mixture in a crucible. The slaking of calcium oxide made according to my process yields a compound which does not correspond to the composition by the theoretical reaction between one molecule of sodium hydroxide and one molecule of calcium oxide according to the known chemical formula, but contains a supplemental amount of sodium hydroxide and water in order to 22:: give the mass the required binding and permit the same to remain shaped after calcination at low temperature.

It is noteworthy that according to my process, I obtain a soda-lime brick, which contains a much higher proportion of sodium hydroxide when compared to any other known process and which is, therefore, adapted to absorb a higher percentage of carbon monoxide before having to be regenerated. The process is carried out as follows: Calcium oxide is slaked by means of or in a solution of sodium hydroxide according to the usual method of manufacturing soda-lime, and this well known operation need not be further explained to those skilled in the art. Such slaking yields a pasty, almost solid mass, which I calcine in a crucible to dryness and which may then be called quick-sodalime.

Such quick soda-lime will then be slaked by a solution of 5% of sodium hydroxide at 95 C in a proportion of 800 grams per kilogram of soda-lime, whereby-flower of sodalinie will be obtained. Such flower of sodalime will be brought into a conical separator,

trial No. 359,418.

closed and provided with a ventilator, so as to remove any non-slaked particles which could obstruct the passage of gas in the retorts during the operation. Then it will be discharged into molds provided with partitions forming rectangular volumes of about 50 x 100 x millimeters. Said partitions rest on a movable bottom forming an ejector. Said molds are arranged. on an endless belt and submit the soda-lime powder to the sprinkling of a solution of soda-lime milk or sodium chloride solution at C. Such sprinkling will be efiected progressively so as not to form a liquid paste in the molds and cause the solution to slowly impregnate into the soda-lime in a hot and powdered state, a second sprinkling being effected only after the first one has filtered through the powder of soda-lime. The number of sprinklings is calculated in such a way that at the end of the endless belt the molds will contain a sort of bricks of hydrated soda-lime which may be easily removed and placed upon wooden hurdles in order to obtain a definite shape.

A substantially similar result may be ob tained by a mixing operation, but the method above described has the advantage over a mixing operation in that the method does not compress or triturate the soda-lime and fur-- ther results in a fine brick containing 1250 grams of the hot solution for two kilograms of soda-lime powder. Said solution will slowly impregnate the powder and solidify the same, at the same time giving same such high porosity and moistness that it will be particularly convenient for absorbing quickly the CO contained in the water gas. The bricks of about 50 x 100 x millimeters placed upon hurdles will be quickly dried by the action of the heat contained in the paste and havingthe great advantage with relation to any smaller product that they have but a few faces to be dried and therefore keep the moistness as long as possible.

This operation serves to exactly proportion the soda-lime powder with a hot solution, thus producing bricks which may be used a few hours after their manufacture without previous drying. The degree of moistness Will considerably influence the result of the purification of the hydrogen, saving time in heating, securing a longer period of purification, a better preservation of steam and particularly less:sintering intheregeneration of soda-lime.

The hydrated soda-lime bricks after a few hours have a solid, porous shape adapted to be handled. Said bricks will' be manufacture'd in sizes suitable for theretorts intended to receive the same. 'Thelarger theretort,the longer the bricks but of the same thickness.

For the purpose of puriying the-- retorts prior to the use thereof, a solution ofcaustic soda or potash Will be slightly vaporized on the brick. to removeianylGa iand contained :inlthei'retort: androarbonate the faces: of the latter.

Having now fully described-'myisaid invention, what I- claim and desire toiseoure byiLet- 'ters Patent, is

1. A process ofipreparin'g sodalime in the shape of porous bricks containingia highproportion of: sodium.hydroxide/and:adapted to purify hydrogen ifrom carbon nmonoxide,

iihich i consists in preparing ordinary; asodalime byslaking calcium oxideiby HBGH-HSiOf-a solution oi sodium hydroxide, calcining said soda-lime,i'efiecting1 over. saidrcalcined: sodadim'eta series"ofE sprin-klings byimeans jofaa solution of sodium hydroxide adapted tolcoagulatesaid calcine'd soda-lime in the shape of solid bricksiir suitablermolds,-removing "said bricks from said molds-and; partly drymg sa-i'd bricks before use.

2. A process of preparing soda-limein the shape of porous brickscontaining'a higlrproportion of sodium hydroxide-and: of: purifyin'g hydrogen from -:carbon monoxide by 40 means of said bricks, which consists izxrpreparing ordinaryxsoda-lime by slaking calcium oxide by :a suitableisolution of". sodium hydroX- a ide,#calcining= said. sodael ime by-means' of-a hot diluted solution OZELSOdlIlHI 'hydroxidef for obtaininga powder of sodarlime, distributing .1 said; powder: in a seriesiof 1110lClS -2LdaPt6dItO for-1n prismaticbricks of convenient'shape;.ef fe'cting over said powder of ssoda-lime in molds a series of sprinklings by means "of 'a Warm solution ofsodium hydroxide-until-said powder of sodaslime 'is 1 coagulated Y in the molds in shape ofsolid bricks; removing said 'brioks" fromsaid molds, partly drying :said bricks, placing saidr bricks in'retorts adapted 420 be heatedyand conducting the'hydrogen 1 to be. purified through said-'retorts.

,JULI-EN BELLAY. 

